I run my top vent on my GOSM about 1/4 open.....but I quit using small chips/chunks, and have taken to using the biggest chunks I can find, and fit into the chip box that came with the smoker, I can get about 1.5-2hrs of thin blue, I found that the smaller chips are hard to keep the smoke thin and blue, the gosm is an awesome smoker, you just have to figure out what makes her purr.....Sorry about the brisket, I think you are on the right track with the bbq sauce/pulling, but time will only increase the smoker flavor, maybe try trmming the bark off and then pulling, the bitter taste comes from the creosote that has collected on the outside of your meat.